2/6. John has developmental amnesia. He was born prematurely and the area of his brain that mediates his memory for day-to-day events was damaged. However, his ability to acquire long-term memories was spared, and with help from his diary and a mobile phone, John, now 29, gets round many of his memory failings. Cognitive neuroscientist Professor Faraneh Vargha-Khadem explains why John's memory works this way.